This is a clinical research study designed to evaluate sildenafil for the treatment of Pulmonary Arterial Hypertension in children, aged 1 to 17 years. The purpose of the study is to assess the efficacy, safety, and pharmacokinetics of 16 weeks of chronic treatment with oral sildenafil given in three different doses, compared to placebo (inactive treatment). Efficacy will be measured by exercise and hemodynamics. Patients who complete this trial may be eligible to take part in an extension study, in which all patients will receive active treatment of sildenafil.

mPAP, a hemodynamic parameter, was measured using a pressure transducer positioned at the mid-axillary line with the patient in the supine position. Change is observed value at Week 16 minus Baseline value.

Females of child bearing potential who were sexually active must have been practicing a suitable method of birth control so that in the opinion of the investigator, they would not become pregnant during the study.

Subjects who have symptomatic pulmonary arterial hypertension due to: primary pulmonary hypertension; pulmonary arterial hypertension in the presence of a small or hemodynamically insignificant congenital systemic to pulmonary shunt lesion that in the opinion of the investigator is not the cause of pulmonary hypertension; collagen vascular disease; congenital systemic-to-pulmonary shunts with a baseline resting room air oxygen saturation >= 88% unrepaired or repaired at least 6 months prior to screening; d-transposition of the great arteries repaired within the first 30 days of life; or surgical repair of other congenital heart lesions at least 6 months prior to screening and do not have clinically significant residual left-sided heart disease consistent with the exclusion criteria.

Written informed consent and assent where applicable before the subject is screened for the study.

Subjects who undergo a large shift in altitude (defined as approximately 5000 feet or 1524 meters) in order to participate in the study must reside at the "in study" altitude for at least 90 days prior to baseline and during the study period.

Exclusion Criteria:

Subjects with pulmonary hypertension secondary to sickle cell disease, any other disease known to be associated with PAH, or any etiology other than those specified in the inclusion criteria.

Any medical or psychological condition or social circumstances that would impair their ability to participate reliably in the study or who were not likely to complete the study for any reason; current or past illicit drug use or alcoholism excepting if abstinence can be documented for >= 1 year.

Participation in another clinical trial of an investigational drug or device (including placebo) within 30 days of screening for entry into the present study.

Subjects with known hereditary degenerative retinal disorders (such as retinitis pigmentosa) or history of non-arteritic anterior ischemic optic neuropathy (NAION).

Contacts and Locations

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To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00159913